The invention relates generally to sewer interior video inspection devices and more particularly to devices for inspecting lateral sewer pipes.
A lateral inspection device is disclosed in U.S. Pat. No. 5,992,247 titled xe2x80x9cApparatus For Inspecting Lateral Sewer Pipesxe2x80x9d and assigned to the Assignee of this application. The lateral inspection device disclosed in that patent includes a lateral camera, a main camera, and a self propelled sled for moving the cameras through a sewer main. The main camera is mounted on an adjustable chute which carries the lateral camera. The chute can be rotated to change the orientation of the lateral camera in the sewer lateral. Because the main camera is mounted on the chute, the main camera moves with the chute as the chute is moved to orient the lateral camera. An above-ground operator views the relative positions of the lateral camera and an opening to a lateral sewer pipe through the main camera. When the lateral camera is close to the lateral sewer pipe opening, the chute is moved to properly align the lateral camera with the opening to the lateral sewer pipe. The lateral camera is pushed into the lateral sewer pipe by a driven push rod. All the necessary electrical wiring for video and light power for the lateral inspection camera is carried by the push rod.
Several problems with prior art lateral inspection devices, including the device described above, have been observed. The present invention addresses these problems and includes additional improvements over prior art lateral inspection devices.
One problem identified in the prior art is that the main camera is mounted on the launch chute for the lateral camera. Because of this prior art construction, the main camera is moved along with the chute with respect to the apparatus frame. Moving the main camera with respect to the frame of the apparatus may result in the disorientation of the above-ground operator and loss of the lateral pipe opening from the field of view of the main camera.
Another problem in prior art constructions is that the above-ground operator is only able to view images transmitted by one of the cameras at a time. There are often blockages in the lateral pipe requiring the apparatus to move back and forth to ram the lateral camera past the blockage. There are two primary concerns when trying to ram the lateral camera past a blockage. The first is to confirm when the lateral camera has cleared the blockage, and the second is to make sure that the apparatus has not moved significantly past the lateral pipe opening during the ramming procedure, which may result in snapping the push rod. The first concern is addressed by looking through the lateral camera, and the second is addressed by looking through the main camera. The prior art construction permits the above-ground operator to receive images from only one camera at a time. This hinders the process of moving the lateral camera past a blockage because of the constant switching between the cameras that is required.
Other improvements that could be made to prior art constructions include providing better lighting in the main pipe for the location of lateral pipe openings, providing better protection for the main camera in the event of a roll-over of the apparatus, providing a means for determining how far the lateral camera has advanced into the lateral pipe, and providing a means for mapping the lateral pipe underground to facilitate horizontal, underground drilling for utility lines and the like. As will be discussed below, each of these improvements are met by the present invention.
The present invention provides an apparatus that travels along an underground main pipe and that permits inspection of an underground lateral pipe. The apparatus includes a frame and main camera mounted on and fixed with respect to the frame. The apparatus also includes a lateral camera and/or a beacon. The lateral camera and/or beacon is moveable with respect to the frame and insertable into the lateral pipe by means of a push rod cable.
The beacon may be mounted on the lateral camera or provided independently on the push rod cable if no lateral camera is provided. The beacon emits a low frequency signal that penetrates the lateral pipe wall and the earth surrounding the lateral pipe. Preferably, the apparatus includes a receiver receiving the low frequency signal above ground and permitting location of the beacon within the lateral pipe. The beacon and receiver permit three-dimensional mapping of the lateral pipes.
A monitor is provided for the use of the above-ground operator. Preferably, the apparatus includes a picture-in-picture (PIP) processor mounted on the frame. The PIP processor permits the above-ground operator to display on the monitor images transmitted by both cameras simultaneously. This facilitates ramming the lateral camera past blockages in the lateral pipes, and also facilitates alignment and insertion of the lateral camera 44.
Preferably, the cameras include wide-angle lenses to maximize the field of view for the cameras at close ranges. Also, light emitting diodes (LED""s) may be provided on each camera to facilitate viewing the inside of the pipes. Preferably, the LED""s of both cameras can be simultaneously illuminated. The additional light from the lateral camera""s LED""s aids in finding the lateral pipe opening with the main camera. A shield is preferably mounted to the frame to protect the main camera from being physically damaged in the event of the apparatus rolling over in the main pipe.
Preferably, a meter is connected to the frame and is used to determine how much of the push rod cable has been inserted into the lateral pipe. The meter may include a Hall Effect sensor. An overlay generator mounted on the frame permits the output of the meter to be selectively displayed on the monitor over the video display.